1. Field of the Invention
The present invention relates to a substrate treating apparatus and substrate treating method for removing organic substances from substrates. In particular, the invention relates to a substrate treating apparatus and substrate treating method for removing a reaction product, which is an organic substance, from substrates. More particularly, the invention relates to a substrate treating apparatus and substrate treating method for removing, by using a removal liquid, a reaction product generated on surfaces of substrates having a patterned film formed by dry etching using a resist film as a mask.
2. Description of the Related Art
In manufacture of semiconductor devices, an etching process is carried out to make a pattern, by using a resist film as a mask, from a film (e.g. a film of metal such as aluminum, copper or the like) formed on the surface of a substrate, e.g. a semiconductor wafer. For forming a microcircuit pattern in the etching process, dry etching such as RIE (Reactive Ion Etching) is employed.
Reactive ions used in dry etching have such strong power as to resolve the resist film to some extent before the etching of the film is completed. Part of the resist film undergoes a change in property, turns into a reaction product such as a polymer, and deposits on side walls of the film. This reaction product cannot be removed in a resist removing process to follow. It is therefore necessary to remove the reaction product after the resist removing process.
Conventionally, therefore, a reaction product removing process is carried out after the resist removing process, to remove the reaction product from the side walls of the film by supplying the substrate with a removal liquid capable of removing the reaction product.
The above “reaction product resulting from a change in property of the resist” is an organic substance. A process may also be carried out to supply the substrate with an organic substance removal liquid for removing other organic substances from the substrate.
Generally, the removal liquid used in the process of removing such reaction product and other organic substances is the type used at room temperature. Recently, however, a removal liquid has been developed that is used at a temperature higher than room temperature for an enhanced organic substance removing performance. In use, the removal liquid is heated to a proper temperature in the range of 50 to 80° C. to realize a maximum removal rate.
However, even when the removal liquid is heated to the proper temperature, the removal liquid actually supplied to the substrate loses some of its heat to the substrate, thereby to cool below the proper temperature. Thus, even the use of the removal liquid heated to the proper temperature achieves only a low efficiency of removing reaction products, to impair the quality of substrate treatment.
To deal with such a problem, it is conceivable to supply the substrate with the removal liquid heated a temperature above the proper temperature. However, the composition of the removal liquid is sensitive to temperature variations. When the removal liquid is heated above the proper temperature, a change in the composition reduces its ability to remove reaction product.